Microwave oven



FIG. 1 is a front, right side and top perspective view of a microwave oven showing our new design,

FIG. 2 is a rear, left side and bottom perspective view thereof,

FIG. 3 is a top plan view thereof, and

FIG. 4 is a right side elevational view thereof. 

The ornamental design for a microwave oven, as shown. 